This invention relates to the detection of microbial pathogens. In another aspect, this invention relates to a novel device useful for mixing and centrifugation of fluid samples. In still another aspect, this invention relates to a novel device which is used for admixing a sample fluid containing microbial pathogens with a treating fluid and thereafter selectively extracting the microorganisms from the sample fluid. In still another aspect, this invention relates to a novel method and apparatus for diagnosing septicemia.
Septicemia which is the presence of pathogenic microorganisms in the blood is one of the most serious types of infection encountered. In spite of an armament of antibiotics and fungal drugs, the mortality rate from septicemia is approximately 25%. In addition, when shock accompanies septicemia, the mortality rate increases to over 60%. Patients who are suffering from debilitating diseases, undergoing major surgery, receiving immunosuppressive drugs, or anticancer medications are particularly prone to septicemia.
Early administration of appropriate antibiotic therapy is important in fighting septicemia. Consequently, it is imperative that the physician know as rapidly as possible not only whether the patient has septicemia, but also the identity of the infecting organisms, and the susceptibility of the microorganisms to antibiotic agents. Thus, the proper diagnosis of septicemia depends upon very rapid and efficient quantitative analysis of the patients blood. It is imperative during the quantitative analysis of the patients blood or other body fluid that the sample fluid not be contaminated with pathogens from the laboratory environment.
The conventional methods and equipment which are utilized to detect microorganisms in the blood sample suffer from one or more serious drawbacks which include a lengthy detection time, not being quantitative, and not able to detect the presence of different types of microbial pathogens within a sample, and being susceptible to contamination by laboratory atmosphere and personnel.
Recently, an improved method has been developed for determining the presence of microbial pathogens within a sample fluid which is extremely rapid and quantitative and minimizes contamination of the sample from the laboratory environment and personnel. This method is disclosed in copending U.S. Pat. application Ser. No. 428,135 filed Jan. 9, 1974, and entitled "DETECTION OF MICROBIAL PATHOGENS". According to this improved method for the detection of microbial pathogen, a sample of body fluid such as blood (preferably a lysed blood sample) is deposited upon a liquid filter medium within a confined sterile zone. The liquid filter medium has a density greater than the sample fluid and comprises a sterile aqueous solution which will selectively receive microbial pathogens from the sample fluid. Thereafter, the confined sterile zone is subjected to centrifugation to force the sample fluid against the liquid filter medium and cause the microbial pathogens to selectively pass therein and thereby separate from the mass of the body fluid sample. Next, the liquid filter medium containing the microbial pathogens is separated from the remainder of the sample fluid and portions of the liquid filter medium are subjected to culturing conditions. An improved apparatus for carrying out the novel method is disclosed in copending application Ser. No. 437,890 filed Jan. 30, 1974, and entitled "APPARATUS AND METHOD FOR THE DETECTION OF MICROBIAL PATHOGENS".